Validate incoming GPS data (#951)

* Validate incoming GPS data and throw an error if it is incorrect, storing Null values

* Extracted GPS data processing to function in external parser; optimized IF in internal parser; removed unnecessary comments; set exact values for positive test

* Add the migration for removing existing invalid GPS data and its test; added better errors to asserts in the GPS validation test

* Install FFmpeg and ExifTool on the API unit-test environment

* Fix 'stripped.jpg', 'IncorrectGPS.jpg', and 'CorrectGPS.jpg' tests for the external parser

* Optimized data validation in the external parser, returned error by the internal parser for invalid data, updated test to expect errors and handle them

* Switched from error to log entry in case of incorrect GPS data, as error handling is not so transparent in the internal parser

---------

Co-authored-by: Konstantin Koval

api/database/migrations/exif_invalid_gps_test.go

@@ -0,0 +1,74 @@
+package migrations_test
+
+import (
+	"bufio"
+	"math"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/photoview/photoview/api/database/migrations"
+	"github.com/photoview/photoview/api/graphql/models"
+	"github.com/photoview/photoview/api/test_utils"
+)
+
+func TestExifMigration(t *testing.T) {
+	envFile, err := os.Open("/home/runner/work/photoview/photoview/api/testing.env")
+	if err != nil {
+		t.Fatalf("Failed to open environment file: %v", err)
+	}
+	defer envFile.Close()
+
+	scanner := bufio.NewScanner(envFile)
+	for scanner.Scan() {
+		line := scanner.Text()
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) != 2 {
+			t.Fatalf("Invalid line in environment file: %s", line)
+		}
+		key, value := parts[0], strings.Trim(parts[1], "'")
+		os.Setenv(key, value)
+	}
+
+	db := test_utils.DatabaseTest(t)
+	defer db.Exec("DELETE FROM media_exif") // Clean up after test
+
+	// Create test data
+	exifEntries := []models.MediaEXIF{
+		{GPSLatitude: floatPtr(90.1), GPSLongitude: floatPtr(90.0)},   // Invalid GPSLatitude
+		{GPSLatitude: floatPtr(-90.1), GPSLongitude: floatPtr(-90.0)}, // Invalid GPSLatitude
+		{GPSLatitude: floatPtr(90.0), GPSLongitude: floatPtr(90.1)},   // Invalid GPSLongitude
+		{GPSLatitude: floatPtr(-90.0), GPSLongitude: floatPtr(-90.1)}, // Invalid GPSLongitude
+		{GPSLatitude: floatPtr(90.0), GPSLongitude: floatPtr(90.0)},   // Valid GPS data
+		{GPSLatitude: floatPtr(-90.0), GPSLongitude: floatPtr(-90.0)}, // Valid GPS data
+		{GPSLatitude: floatPtr(90.1), GPSLongitude: floatPtr(90.1)},   // Invalid GPSLatitude and GPSLongitude
+		{GPSLatitude: floatPtr(-90.1), GPSLongitude: floatPtr(-90.1)}, // Invalid GPSLatitude and GPSLongitude
+	}
+
+	// Insert test data
+	for _, entry := range exifEntries {
+		assert.NoError(t, db.Create(&entry).Error)
+	}
+
+	// Run migration
+	assert.NoError(t, migrations.MigrateForExifGPSCorrection(db))
+
+	// Validate the results
+	var results []models.MediaEXIF
+	assert.NoError(t, db.Find(&results).Error)
+
+	for _, entry := range results {
+		if entry.GPSLatitude != nil {
+			assert.LessOrEqual(t, math.Abs(*entry.GPSLatitude), 90.0, "GPSLatitude should be within [-90, 90]: %+v", entry)
+		}
+		if entry.GPSLongitude != nil {
+			assert.LessOrEqual(t, math.Abs(*entry.GPSLongitude), 90.0, "GPSLongitude should be within [-90, 90]: %+v", entry)
+		}
+	}
+}
+
+func floatPtr(f float64) *float64 {
+	return &f
+}